I nearly revived THIS 6 year old thread because I used the search function well and have this same issue, but I decided against it because it's about a '95 so I'd be posting in the wrong section for my '85 4Runner.

What I didn't find in that thread was a solution or suggestions for troubleshooting, so...
My wipers worked fine this morning. After work, they were stuck on as soon as I turned the key to start the truck. They will go into "high," but otherwise it is stuck on low - "delay" and "off" have no effect. I have temporarily disabled them by pulling the fuse by the clutch.

We had a good rain overnight and while I was at work today, maybe I got some water in where it shouldn't? I know my windshield, firewall, sunroof, or some combination of all 3 are leaking because I get water in the cab now and then. Is there a relay I need to check for wetness?

I'm gonna go dig into my FSM and/or Haynes but I wanted to get some troubleshooting pointers here as well. Thanks for any help!

 

You should definitely make sure that the low speed wire to the wiper motor is dead when the switch is in the off position, but your symptoms point to the wiper parking mechanism inside the wiper motor. There is one wire to the motor that is always hot when the key is on that permits the wipers to run until the blades reach the parked position. If the parking mechanism fails to open a pair of contacts inside the wiper motor when the blades reach 'park', the wipers will never shut down.

 

I think I'm smart enough to verify the switch is OK once I take the column apart, just look for wires to be hot when the switch is on but dead when the switch is off. I haven't done something like that but I think I could work it out.

The motor is a different story. It looks to be about a $45 part - not too expensive to replace, but too pricey to troubleshoot by replacing. Do I need to unmount my motor from the passenger firewall in order to look for those contacts that park the wipers? It sounds like I'll need to take it apart.

No relays to check out? I'm considering a switch setup that will let me cut power to the wiper circuit so I can turn it on only when needed. The heavy dew in the morning has made for an annoying commute with no wipers.

 

One thing to add...
When you remove the motor do not remove the nut to the wiper link. Simply pull the motor out a few inches and pop the ball joint union, it's the first link after the motor. And remove the motor with that arm attatched.
This will keep you from misaligning the wipers for when there in the park position.
I spent a couple hours last night figuring out why the wipers would stop in the middle of the windshield after reinstalling the motor.

When you open it up take pictures!

Wiper relay is inside passanger side kick panel...

 

The first thing I looked at might have paid off. I pulled out the wiper relay behind the passenger kick panel, and once I got it unhooked and stared to take it apart about a tablespoon of water dumped out of the housing. Resealing the windshield might need to move up on my list a bit.

Here's the relay drying in the sun

 

Excellent. Looks like you found the issue.
Do you by chance have a variable speed on your switch?

 

That ended up being it. Bumper-in-the-sun drying didn't fully dry it, I could still see moisture under the cover. So I did 2 cycles of baking-stone-in-the-warm-oven. Nothing extreme, just waited till the temp fell below 160ish after we used the oven. Nice dry heat in there, no more moisture visible, wipers work again.


The markings are all worn off the selector switch, so I *THINK* I have: off, delay (~3 seconds between cycles), low, high.

Thanks for the help guys!

Problem solved song time!!